Olfactory host location and host preference of Holepyris sylvanidis (Hymenoptera: Bethylidae) and Cephalonomia waterstoni (Bethylidae), two natural enemies of Tribolium and Cryptolestes species

Parasitoids can suppress populations of their host and thus play a primary role in Integrated Pest Management. In the stored product environment, stimuli deriving from plant products, damaged plant products and hosts might be important for host location by the parasitoids. We studied foraging cues in Holepyris sylvanidis (Hymenoptera: Bethylidae), a larval parasitoid of Tribolium species and Cephalonomia waterstoni (Bethylidae), a natural enemy of the rusty grain beetle Cryptolestes ferrugineus (Coleoptera: Cucujidae). Our studies in a fourchamber olfactometer revealed that the host complexes of both Tribolium species and different living host stages attract naive H. sylvanidis females, whereas no reaction was observed to uninfested substrates. The olfactory response of C. waterstoni was found to be strongly elicited both by chemicals emitted by the dust, adult C. ferrugineus and C. ferrugineus third and fourth instar larvae. Our findings may contribute to the development of biological control strategies of T. castaneum, T. confusum and C. ferrugineus with parasitoids.